Stretching of textile filaments or threads



March 17, 1942. M. w. ALFORD ETAL STRETCHING OF TEXTILE FILAMENTS OR THREADS Filed March 26, 1941 5 Shets-Sheet 1 March 17,1942. M. w. ALFORD ETAL 12,276,364

' ISTRETCHING 0F TEXTILE FILA MENT S bn TH EADS Filed March 26, 1 941 s Sfiefs-Shet 2 M rch 17, 1942.

M. w. ALFORD EFAL STRETCHING OF TEXTILE FILAMENTS OR THREADS Filed March 26. 1941 3 Sheets-Sheet 3 Patented Mar. 117, 11942 arrests entree STATES PATENT QFFESE STRETCHING OF ZEE R 7 I Maitland Walton Alford, Thomas Jackson, and

Frank Brentnall Hill, Spondon, near Derby, England, assignors to Celanese Corporation of American-a corporation of Delaware Application March 26, 1941, Serial No. 385,230 In Great Britain April 3, 1940 18 Claims.

This invention relates to the stretching of textile filaments or threads and in particular to the stretching of textile filaments or threads in a softening medium for such purposes as increasingtheir strength. The invention is especially concerned with operations in which the softening medium employed is a gaseous medium, such has been reached, e. g. up to 5, 10, 20 or more times the original length of the threads. It is an object of the present invention to enable the initial input speed to be reduced, as well as the output; speed, and, besides increasing the output speed from equality with the input speed until the desired speed ratio between input and output has been attained, to speed up the operation as a whole from a low starting speed to the desired production speed.

According to the present invention, in the stretching of textile materials in the form of filaments or threads while they are running through a gaseous softening medium under pressure, the material is caused to run through the softening medium with an output-input speed ratio equal to the .degree of stretch required. and the input and output speeds are then varied while maintaining said ratio substantially constant and the pressure of the gaseous medium is simultaneously varied under the control of the tension in the material as it leaves said softening medium so that, as the tension varies with the change in speed, the softening effect of said medium is varied in a corresponding manner. In this way, stretching 'may be started at a low overall speed, which is then increased to full production speed. Similarly, the operation may be stopped in an inverse manner.

The control of the pressure may convenient y be effected in accordance with the tension in the material being stretched by the provision of a device sensitive to tension, such as a rod mounted on a lightly springor weight-loaded arm, round which rod the material emerging from the stretching operation is caused to turn through an angle, and a relay for amplifying the small and delicate force exerted by the tension in the material on the rod into a powerful force by which a valve determining the pressure may be controlled. For example, the motion of the arms carrying the rod may actuate a needle valve controlling the supply of compressed air to a spring-loaded diaphragm, to which is secured a connecting rod giving a powerful thrust derived from the pressure of the air over the large area of diaphragm.

According to a further feature of the invention a tension-sensitive device and relay of the kind described above may be employed for other purposes. In particular they may be used for controlling also the speed of take-up packages on which the stretched materials are collected, which packages, as they increase in size need to be rotated more slowly in order to take up the material at a constant linear rate. This may be done by causing the relay to control an infinitely variable gear-box driving the packages,

and indeed the device may be applied to all cases where delicate control of tension is desired and where infinitely variable gears or like regulators -;are in use.

The increase in speed, together with a cor responding increase in pressure in accordance with the invention, may conveniently be carried out after the desired ratio between the input speed of the material and the outputspeed has been attained by suitable means, e. g. by the means described in U. S. application S. No.

372,108 referred to above, or by the use of an plication S. No. 375,420 filed January 22, 1941, in which material to be stretched is supplied to a stretching chamber containing a softening medium under pressure froma food chamber which contains a medium under pressure but a lower pressure than that of the softening medium in the stretching chamber. According to U. S. application's. No. 375,420, means are provided whereby the pressure in one of these two chambers, preferably the feed chamber, is

controlled in accordance with the pressure in devices by which these efiects are brought about for the purposes of the prior specification may well be adapted for the purposes of the present invention. Thus, the means by which the pressure is held at a desired amount may be placed under the control of thevtension-sensitive device referred to above so that the desired amount, constituting the upper limit of the pressure under the control of the device, may itself be steadily increased under the control of the tension in the materials being stretched. In this way, when the tension increases as a result of an increase in the rate of travel of the material, the pressure in the stretching chamber may be increased, so that the rate of softening of the material is increased to correspond with the increased rate of travel.

By way of example one arrangement of ap-.- paratus'suitable for carrying out the present invention, and incorporating the device described in U. S. applications S. No. 372,108 and S. No. 375,420 mentioned above, will now be described in'greater detail with reference to the accompanying drawings in which:-

Figure 1 is a diagrammatic side view of the apparatus as a whole;

Figure 2' is a diagrammatic plan view of part of Figure 1;

Figures 3 and 4 are a side elevation and plan view respectively of a tension-sensitive device employed for the purpose of the invention;

Figure 5 is a sectional elevation of a mechanical control means under the pneumatic control of the device shown in Figures 3 and 4, and

Figures 6 is a diagrammatic side view of a modification of the apparatus as a whole. f

In the apparatus shown in Figure l, a number of threads I-are taken from bobbins 2 mounted in a creel 3, are led through guide-eyes 4 in connection with the, creel 3 and proceed from the guide-eyes l to a spacing comb 5. From the comb 5' the threads I enter a stretching apparatus of the general form described in U. S. Patent No. 2,053,278. This comprises a feed chamber 6 having apertures I through which the threads enter and containing nip-rollers 8 by means of which the rate at which the threads are drawn into the stretching apparatus is accurately controlled, From the feed chamber lithe threads I pass to a stretching chamber 9, entering through apertures I9 and leaving through apertures I I. During the stretching'operation the stretching chamber 9 is supplied through a pipe I2 with moist steam under pressure and the feed chamber 6 is supplied with compressed .air through a pipe I3. The compressed air in the chamber 3 is supplied at a pressure slightly lower than that of the steam in the chamber 9 and minimises the flow of steam from the chamber 9 through the apertures I0, so that the threads, softened in the chamber 9, are not broken by being blown back into the chamber 8.

During the initiation of the stretching operawise direction from above, and the pull of the threads I between the pulleys I4 and I5 initially counteracts the pressure of the spring I9 The compensator bar I6, with its pulleys I5 and I 8 and spring I9 together constitute the tensionsensitive means described and claimed in U. S. application S. No. 372,108,. On their way to the fixed guide pulley I 4 the threads pass (but do not at first engage with) a tension-sensitive device, indicated generally in Figures 1 and 2 at 29, and described in greater detail with reference to Figures3 and 4. While the threads are engaged with the members I I-I9, as shown in Figure 1 and in dotted linesin Figure 2, they pass beneath the device 20; they are not threaded up through the device 20 as 'shown in full in Figure 2 until, at a later stage, they are disconnected from the members I4---I9.

The pulley I8 guides the rope of threads I to a conical roller made up of three parts 2|, 22 and 23, the parts 2I and 23 being cylindrical and having diameters proportional respectively to the unstretched length of the threads and the stretched length desired. The part 22 is the conical part, and connects the parts 2I and 23. The length of the part 22 and the position of the point I! are arranged so that the pulley I8 is always close to one or other of the parts 2|, 22, 23, and guides the threads I passing overit accurately to the conicalroller, to the under side of which the threads pass.

Co-operating with the large part 23 of the conical roller is a further roller 24 constituting, with the roller 23, a pair of nip-rollers similar to the rollers 9 in the chamber 6. Beyond the rollers 23 and 24 the threads encounter a comb 25, a set of three drying drums 26, a further comb 21, a pair of mangle rollers 28 and a take-up creel for the collection of the stretched threads. The comb 21 and the mangle rollers 28 are wider than the nip-rollers 8 and 24, being of a size appropriate to the width of the take-up creel, the creel comprising a waste swift 29 and take-up bobbins 3|.

The steam is fed by the pipe I2 to the stretching chamber 9 through a steam valve 32 under the control of pressure-sensitive pressure controller, indicated generally at 33, operated by compressed air. The steam valve 32 is adjusted, to maintain a desired steam pressure in the steam chamber 9, by means of a spring-loaded diaphragm 34 subjected on one side to an air pressure supplied through the pipe 39 by the controller 33. Fora full understanding of the invention in the particular application of it here described, it is desirable to refer in some detail to the manner in which the controller acts and the functions which, directly or indirectly, it performs.

Air is supplied to the controller 33 at a pressure of 17 pounds per square inch from the air supply main I3 and valves 35, 36 through a branch pipe 31 and a suitable reducing valve 38. The air so tion the supply of both steam. and air through the pipes I2 and I3 respectively is at first shut f 01!, so that the threads I may be led through the chambers 6 and 9. The threads'emerging urges the compensator bar I6 in a counter-clocksupplied is able'to pass through one valve 39 into a pipe 49 communicating with the diaphragm 34 of the steam valve. and is able to pass from the pipe 40 through another valve ll controlling a leak 42, whereby the air may escape into the atmosphere. The two valves 39, 4| controlling the air in this manner are coupled together by a member 43, so that as one opens the other is closed, and by these means the air pressure applied to the diaphragm 34 or the steam-controlling valve 32 is varied. Thus, by opening the valve 39 by which the air reaches the diaphragm 34 and by closing the valve 4| by which the air escapes through the leak 42, the pressure applied to the diaphragm 34 may be increased to any degree up to a limit of 17 pounds per square inch, while by closing the valve 39 and opening'the valve 4|, the pressure applied to the diaphragm 34 may be reduced, if necessary to atmospheric pressure. The position of the coupled valves 39, 4| controlling the air is determined by the air pressure in a bellows 44. the bellows being in communication withan air line 45 through which air from the supply at 17 pounds per square inch, after passing through a suitable flxed throttling device 58, escapes'by a controlled leak to the atmosphere. The controlled leak is in the form of a nozzle 5| from which the exit of the air is opposed by a pivoted flapper 52. The flapper 52 is connected bya lever and link 46, 41 to a pressure sensitive element 53, in the form of a Bourdon tube subjected through a pipe 54 to the pressure in the steam chamber 8, i. e. the pressure it is desired to control. in the steam chamber 9 is high, the flapper 52 is pivoted closer to the nozzle 5|, so increasing the pressure in the air line 45 behind the nozzle, and when the steam pressure is low the flapper 52 is pivoted away from the nozzle 5| and reduces the pressure behind the nozzle. Accordingly, the pressure in the bellows 44 in communication with the air line 45 is made to depend upon the pressure in the steam chamber 9, ahigh pressure in the steam chamber 8 increasing the pressure in the bellows 44, while a low pressure decreases the pressure in the bellows. The expansion of the bellows 44, and the consequent movement to the left of the member 43 are arranged to close the valve 39 admitting air to the steam valve diaphragm 34 and to open the valve 4| by which air escapes through the leak 42, and the resulting drop in the pressure applied to the diaphragm 34 closes, the steam valve 32 and reduces thesteam pressure. By these means, the pressure in the steam chamber 9 is maintained at the desired level. A pen 5 is secured to the flapper 52, so as to record on a chart 56 the pressure in the steam chamber 9 as communicated to the pressure sensitive element 53 controlling position of the flapper 52, about its axis, 51.

In order to reduce .the sensitivity oi -the con; troller 33, so as to avoid hunting, the air'escaping from the nozzle 5| is caused to pass through an elastic bellows 62 adapted to absorb any violent fluctuations of pressure behind the nozzle. For the same purpose, a leak 63 is provided in the air line 45 immediately before the elastic bellows 62. The leak 63 is controlled by a valve 64, which may be adjusted so as to adjust the sensitivity of the controller 33 and is coupled with a throttling valve 65 in the air line 45. The two valves 64, 65 are adjusted together by hand. When the leak 63 is shut and the throttling valve 65 full open, the sensitivity is greatest. By slightly opening the leak 63 without much affecting the throttling valve 65 the sensitivity may be reduced. By widely opening the leak 63 and When the pressure the nozzle 5| is pivoted as the flapper 52. r The nozzle 5| is connected by means of a lever 58 and a link 66 to one arm 61 of a bell-crank lever, which is pivoted at 68 on another lever 69, which, for the purposes or the mechanism here described, may be regarded as stationary. The other arm 10 of the bell-crank lever is connected by aframe 1| and link 12 to a point 13 between two elastic bellows 14, 1.5, both of which coinmunicate with the space behind the diaphragm 34 of the steam valve 32. One of these bellows 14, communicates directly with this space and the other, 15, through a substantial capillary about the same axis 61 resistance 16. Thus, any change in pressure hehind the diaphragm 34 is immediately communicated to the bellows 14, so that the point of con- After a time lag, depending on the magnitude of the capillary resistance 16, the same pressure-is communicated to; the other bellows *15 which acts against the bellows 14 and restores the nozzle 5| to its original position.

The compressed air for the feed chamberi is supplied in the manner described and claimed in U. S. application S. No. 375,420. The compressed air, coming from the main |3 through the valves 35, 36 reaches the feed chamber 6 through an air supply valve 11 actuated by. a spring loaded diaphragm 18, one side of which is exposed to the pressure of the steam in the stretching chamber through a pipe 18 branching off the pipe 54. The other side of the diaphragm. 18 is subjected to an'air pressure existing between a pair of coupled valves 88, 8| through which, in series, air supplied from the air main |3 escapes by a leak 82. The coupled valves 80, 8|, together constituting a setting valve, are actuatedby a diaphragm 83, loaded by a spring 84 whose pressure is adjustable by means of a screw 85, and exposed on one side, through a pipe 86, to the air pressure in the feed chamber 6, and on the other, through a pipe 88, to the pressure between 83,.the difierence in pressure maintained on the nearly closing the throttling valve 65, the leak at the nozzle 5| is rendered inefiective, and the steam valve 32 may then be controlled by hand, by manipulating the reducing valve 38 through which air is supplied to the controller 33.

As an additional precaution against hunting, means are provided whereby relative movements between the nozzle 5| and the flapper 52 are damped, any movement of the flapper 52 being at first accompanied by a corresponding move ment of the nozzle 5|, the nozzle returning after a time to its original position. For this purpose two sides of.the diaphragm 83 may be adjusted to any constant amount, for, unless the pressure difference balances the force of the spring 84, the diaphragm 83 will be distorted, andthe setting valve position altered until balance is obtained. In this way the air supplied to the feed chamber I6 through the air supply valve 11 is under the control of a diaphragm 18, which is exposed on one side to the steam pressure and on the other to a pressure differing by a constant amount from the pressure in the feed chamber 6. Thus, any change in the steam pressure is com,- municated to the valve 11 controlling the air supplied to the feed chamber 6 and produces a corresponding change of air pressure in the feed chamber 6. The valves 32, 31, and 8| are more fully described in U. S. application S. No. 375,420.

In order to adjust the desired pressure in the steam chamber 9, (and consequently also the air pressure in the chamber 6) the nozzle 5|. which cmoperates with the flapper 52 may be ad-' justed about its pivot 51 independently of the movement given to it by the bellows 14, 15 as described above. For this purpose the lever 69,

on the point 68 of which the bell crank lever 61, 10 is pivoted, is connected by means of link 38 and lever 9| to a worm wheel 92 actuated by means of a worm 93 on a spindle 94 extending outside the controller 33. The lever 09 pivots' 'against the chart 56 the pressure that the contrr ller 33 is set to give by means of the spindle 94.

The spindle 99 is provided with a knob 98 for hand setting,'-but carries in addition a small pinion 99 engaging with a larger pinion I by means of which it may be automatically set. For the purpose of the present invention the spindle 94 is controlled through pinions 99, I00 by the tension sensitive device 20 in the following manner.

The tension sensitive device 210 comprises, as shown in Figures 3 and 4, a fixed guide bar IM and two movable guide bars I02, I03 connected by a bar I04 to form a frame, which is pivoted in ball bearings I05. disposed at the axis of the bar I03. A block I06 to which the bars I02, I03, I04 are connected carries two screws I01 on which .weights I08 are adjustably mounted so that the whole assembly I02--I08 may be brought out of balance, tending, in Figure 3, to rotate in a clockwise direction. The threads I pass under the bars IOI, I03 and over the bar L02 so that the tension in them prevents the rotation of the bars I02, I03 under the out-of-balance forces due to the weights I00. Fixed beneath the block I06 is a needle valve I 09, the spring loaded needle IIO of which is provided at its upper end with a spherical bearing surface III engaging with the under side of the block I06. Compressed air is supplied to-the needle valve I09 through pipe H2 and leaves it through the pipe II3. A screw H4 on an extension II5 of the needle valve I09 limits the upper position of the valve needle I I0. By these means the position of the needle H0 is regulated in accordance with the tension in the threads I passing under the bars IOI, I03 and over the bar I02, a higher degree of tension in the threads I opening the valve I09 and a lower degree allowing the valve to be closed under theinfluence of the adjustable weights I08.

As shown in Figure 1 the pipe I I2 branches ofi the pipe 31 supplying the controller 33 with compressed air, a reducing valve H8 being included in the pipe II2 to reduce the pressure of the air, which is supplied by the valve 38 at 17 lbs. per square inch, to a pressure of about 1 lbs. per square inch. The pipe II3 leaving the valve I09 leads to a spring loaded diaphragm III shown in greater detail in Figure 5. The diaphragm H1 is enclosed on one side by a casing escape from the casing H0 by means of a leak H9. The leak I I9 is a fixed leak, in the form of.

a nozzle offering a resistance to the escape of a r. If desired, however, the leak may be in the form of a valve close to the valve I09, and coupled therewith to operate in the same manner but in the opposite sense, like the valves 39 and H8, and air behind the diaphragm II'I may one end to the diaphragm, the other end of the rod I2I extending into a sleeve I22 to which it may be secured, when required, by means of a thumb screw I23. The sleeve I22 terminates in v a rod I24 connected to a crank pin I25 extending from the side of the large pinion I00. By these means the spindle 94, controlling the pressure to which the controller 33 is set, may be regulated by changes in the tension of the threads I leaving the chamber 9'.

The valves 35, 36 in the main air supply I3 are, respectively, a reducing valve, for bringing the air supply down to a convenient pressure of about lbs. per square inch, and a stop valve for the purpose of closing down. A reducing valve 81, and a stop valve 88 are provided in the main steam supply I2 for similar purposes. The reducing valves 35, 33 and 81 are adjusted, and the stop valve 31 opened before the apparatus is started up, the air still being under the control of the air supply valve 11, which is shut.

In starting up the device the threads I are drawn from the bobbins 2 and threaded through the-comb 5 and through the chambers 3 and 9, being collected in the form of a rope at the pulley I4 and proceeding as a rope round the pulleys I5 and I8 and on to the small end 2I of the conical roller. The nip-rollers 8 and the conical roller are then driven at such a speed that the peripheral speed of the nip rollers 8 is equal to that of the small part 2| of the conical roller. A common drive to the nip rollers 8 and conical roller is employed so that their relative angular speeds are positively fixed, the common drive being effected through a P. I. V. gear (not shown), and being initially slower than is ultimately required.

The steam stop valve 81 is then opened and the pressure sensitive pressure controller 33, be: ing disconnected by loosening the thumb screw I23 and set to give an appropriate pressure, allows the steam valve 32 to admit steam to the steam chamber 9, and at the same time the interconnection 54, I9 between the steam chamber 9 and the air valve 11 for the feed chamber 6 admits air to the latter at a lower pressure, determined by the strength of the spring in the air supply valve 11, and the adjustable spring 84.

The steam pressure rapidly' builds up, the air pressure following with the predetermined difference until full pressure is reached in both chambers, at which time the controller 33 operates to keep the two pressuressteady and 'at the required difference. During this short interval of time, the conical roller 2|, 22, 23 draws the increasingly softened threads. in the manner described in U. S. application S. No. 372,108, at a faster and faster rate until the full degree of stretch is reached, although as .yet the over-all speed of the whole apparatus is much below what is ultimately required for production purposes. Then, as in that specification, the threads I are unhooked from the pulleys I4, I5 and I8, cut on v the roller 23 and led over the.comb 25 round the drying drums 26, over the comb 21, through the mangle rollers 20 andso to the waste swift 29. They may then be separated in the dents of the reed 25, so that they run as a sheet, picked off one by one from the swift 29, andled through the I appropriate dents. of the reed 21 to the..take-up packages 3!.

This completes the bringing of the apparatus to full stretch in the manner described in U. S.

applications S. Nos. 372,108 and 3'75 420. The threads I have been disconnected from the device the apertures II in the chamber 9 to the drawing rollers 23, 2d as shown in Figure 2.

The threads are then engaged with the tension sensitive device 20, by threading them over the movable bar I02 thereof, and at the same time the thumb screw I23 is tightened, connecting the rod I2I to the sleeve I22. The speed of the rollers 9 and the rollers 23, 24 is then steadily increased by means of the P. I. V. gear in their common drive, without affecting the rates of their speeds or the degree of stretch effected by them on the threads I. As a result of the increasing speed with which the threads are drawn through the apparatus, the time during which they are in the chamber 9 and under the influence of the steam is decreased. In consequence, they are softened to a smaller degree, and a greater ten-* sion is necessary to bring about the degree of stretch determined by the fixed relationship between the speeds of the rollers 3 and the rollers 23, 24. This increase of tension acts upon the movable bar I02, rotating the block I06 in an anticlockwise direction (Figure 3) whereby theneedle valve I09 is caused to open. The opening of the needle valve I09 permits a flow of air through the pipes H2, H3 to the chamber H3 enclosing thediaphragm III. Except for a small amount necessary to increase the volume of the space behind the diaphragm III, the extra air all escapes through the leak II9, but the, increased rate of flow from the leak II9 requires a higher pressure, which is communicated to the diaphragm III. The diaphragm III moves, under this pressure, against the action of the spring I20 and carries with it the rod I2I, and sleeve I22 connected thereto by the thumb screw I23. This rotates the large pinion I through the rod I24 and the crank pin I25 andconsequently rotates the small pinion 99 and the spindle 94. The rotation of the spindle 94 pivots the nozzle 5| and causes the controller 33 to permit a higher pressure in the chamber 9. The air pressure in the chamber 6 continues to follow the increasing steam pressure in the chamber 9. This process continues until the rollers 8 and the rollers 23, 24 are being driven at full production speed, and in practice the change takes only a few seconds. These few seconds, however constitute a very critical period in the starting of the operation, during which, to avoid breakdown, the pressure of the steam and consequently the temperature and the intensity of the softening efiect must be closely controlled in accordance with the overall speed of the operation. This close control is made possible by the present invention. When full production speed is reached, the needle valve I09 is brought up against the stop .I I4 and the spindle 94 is brought to a corresponding position. At this stage the thumb screw I23 may again be disconnected and the threads may if desired be unthreaded from the tension sensitive device 20.

Termination of the stretching operation may be' effected by reversing the operations described above. First. the threads being threaded in the device 20, the thumb screw I23 is tightened. Then the common drive to the rollers 8 and the rollers 23, 24 is steadily and rapidly slowed down, the increasing softness of the threads due to their greater period in the chamber II causing the .valve I09 to close and so permitting the chamber II8 to be deflated through the leak I I9. This rotates the pinion I00and the spindle 94 and reduces the pressure that the controller 33 is set to give in the chamber 9. When a suitably low speed is reached, the thumb screw I23 is disconnected and the threads are unthreaded from the device 20 threaded up to the device l i-I9,

, and broken beyond the rollers 23, 23, so that they collect on the roller 23. When this has been done the steam is turned ofi at the valve 88 so that the threads I are no longer softened by steam in the chamber 9. Since the threads are still being stretched the turning off of the steam increases the tension in them and this rotates the bar I6 against the action of the spring I9 and causes the guide pulley I8 to lead the threads from the roller 23 down to the small part of the conical roller 2I. A, condition of nostretch is thereby reached and the apparatus may be stopped altogether.

In Figure 6 is shown a form of apparatus similar to that of Figure l. in which the tension-sensitive device shown in Figures 3, 4 and 5 is employed for other purposes in addition to those described with reference to Figures 1 and 2. In

this figure, in addition to the tension-sensitive device 20 there is provided a similar device I30 in substitution for the mechanism I4 to' 22 of Figure 1 and a further device I3I of the same kind for controlling the rate of rotation of the take-up bobbins 3|.

The device I30 engages the threads I as they leave the device 20 and controls a valve I32 in a branch of the pipe II2 coming from the reducing valve I I6. Air passing through the valve I32 is led bythe pipe I33 to a'device indicated generally at I34 and similar in form to that shown in Figure 5. The rod I35 of' the device I34 is connected to a crank pin I36 on a large pinion I31. The pinion I3'I engages with a small pinion I38 secured to a further large pinion I39, and the second large pinion I39 engages with a pinion I40 on the control shaft I of a P. I. V, gear I42. The output shaft I43 of the P. I. V. gear I42 drives the rollers 23, 24 through a chain I44. I

In employing the means described above in place of the means I4 to 22 described with reference to Figure l, the threads are led through the apparatus from the creel 3 to the lower stretching roller 23 and the P. I. V. gear I42 is set to impart to the rollers 23, 24 a speed equal to that of the rollers 8, another P. I. V. gear (not shown) constituting a common drive to the P. I. V. gear I42 and the rollers 8. The threads proceeding from the orifices II in the stretching chamber 9 pass as a sheet to the rollers 23, 24 and, on their way, engage with the tensionesensitive device,

may be led over the roller 24 and through the rest of the device to the take-up bobbins 3|, and

I the whole operation is then' speeded up by means of the common variable speed drive to the rollers 8 and .the P. I. V. gear I42.

The device m, unlike the devices 20 and m,

acts throughout the stretching operation. its purpose being to control the speed of the take-up packages 3| so as to compensate for their in crease in diameter during the winding operation.-

For ,this purpose, the whole take-up deviceis driven by 'a variable speed electric motor I46, the motor I46 being provided with a suitable controlling resistance Ifl. The position of the control I48 of the resistance I41 is determined by the actuating rod I49 of a fluid pressure relay I50 controlled by the tension-sensitive device i3I which engages the threads leaving the drying drums 26. In this way,v as: the diameter of the packages 3| increases, they are not allowed to draw the threads at an increased rate or at a substantially higher tension, since a very slight rise of tension reduces the rate of rotation of the packages 3i and the rate of travel of the threads is kept substantially constant. The relay I50 is connected through the valve I5I I (directly controlled by the device I3 I) in the branch of the pipe H2.

The provision of separate tension devices 20, I30, I3! is necessary, not only because of their different positions, but also because the ranges of tension with which they have to deal are different. Thus, the device I30, which is first employed in starting up, has to deal with threads in the unsoftened state, in which they are capable of exerting together a very substantial t nsion, and also in the fully softened state in which the tension in them is very low. The device 20 has to dealonly with threads in the softened state and is concerned with a much smaller range of variation of tension than the device I30. The device I3l, on the other hand, deals only with threads in the unsoftened state, the threads having been hardened in passing round the drying drums 26. Consequently, the device I3I, like the device 20, is concerned with only a small range of tensions, but the tensions are generally higher than those with which the device is concerned.

to secure by Letters Patent is:

1. In the stretching of textile materials in the form of filaments or threads while they are running through a gaseous softening medium under pressure, running the material through the softening medium with an output-input speed ratio equal to the degree of stretch required, and then varying both the' input and the output speeds while maintaining said ratio substantially constant, and simultaneously varying the pressure of the softening medium under the control of the tension in the material as it leaves said softening medium so that. as said tension varies with the change in speed, the softening effect of said medium is varied in a corresponding manner.

2. In the stretching of textile materials in the form of filaments or threads while they are running through a gaseous softening medium under pressure, running the material through the softening medium with an output-input speed ratio equal to the degree'of stretch required, the full degree of stretch being effected at first at a low speed, and then increasing both the input and output speeds while maintaining said ratio substantially constant and simultaneously varying the pressure of the softening medium under the control of the tension in the material as it leaves said softening medium so that, as said tension increases with the change in speed, thesoftening effect of said medium is increased in a corresponding manner.

3. In the stretching of textile materials in the form of filaments or threadsxwhil'e they are running through a gaseous softening medium under pressure, running the material through the softening medium with an output-input speed ratio equal to the degree of stretch required, bringing the stretching operation to an end by reducing both the input and output speeds while maintaining said ratio substantially constant, and simultaneously varying the pressure of the softening medium under the control of the tension in the material as it leaves said softening medium so that, as said tension is reduced with the change in speed, the softening effect of said medium is reduced in a corresponding manner.

4. In the stretching of textile materials in the form of filaments or threads while they are running through a gaseous softening medium imder pressure, controlling the pressure of the softening medium in accordance with the tension in the material as it leaves said softening medium, causing the material as it leaves the softening medium to turn through an angle whereby the tension in the material exerts a force at the point at which the material turns, amplifying said force by means of a relay, and employing the amplified force to determine the pressure of the softening medium, so that, as said tension varies with the change in speed, the softening effect of said medium is varied in a corresponding manner.

5. In the stretching of textile materials in the form of filaments or threads while they are running through a gaseous softening medium under pressure, drawing the material under tensionout of said softening medium during the initial application thereof to the material, employing the tension in the material asit leaves said softening medium to control the rate of said drawing, and to increase said rate up to desired limit as said tension falls in consequence of the increasing softening influence of said medium during its initial application, thereafter increasing both the input and output speeds while maintaining substantially constant the output-input speed ratio to which the material has been brought, and then placing the pressure of the softening medium under the control of the tension in the material as it leaves said softening medium, so that, as the tension of the fully stretched material increases with the change of speed the softening effect of said medium is increased in a corresponding manner.

6. In the stretching of textile materialsin the form of filaments or threads while they are running through a gaseous softening medium under pressure, running the material through V the softening medium with an output-input speed ratio equal to the degree of stretch required, then reducing both the input and outputspeeds, while maintaining said ratio substantially constant, simultaneously placing thepressure of the softeningmedium under the control of the tension of the material as itleaves said softening medium, so that as said tension is reduced with the change in speed, the softening effect ofsaid medium is reduced in a corresponding manner, and thereafter placing the speed at which .the material leaves the softening medium under the control of the tension in the material as it leaves said softening medium, and cutting off the supply of softening medium to the material, whereby said speed is diminished as said tension falls in consequence of the decreasing softening influence of said medium as its supply is cut off.

'7. Inthestretching of textile materials in the form of filaments or threads in which the material is drawn under tension from a feed chamber into and through a stretching chamber containing a gaseous softening medium under pressure,

controlling the pressure in said feed chamber in accordance with the pressure of said softening medium, whereby the softening medium is maintained at a pressure higher than the pressure in the feed chamber by a constant amount,

running the material through the softening medium with an output-input speed ratio equal to the degree of stretch required, and then varying, both the input and the output speeds, while maintaining said ratio substantially constant, and simultaneously varying the pressure of the softening medium under the control of the tenthe form of filaments or threads while they are running through a gaseous softening medium under pressure, said apparatus comprising a stretching chamber, means for supplying a gaseous softening medium under pressure to said stretching chamber, variable speed means for drawing the material through said chamber with an output-input'speed ratio equal to the degree of stretch required, and tension-sensitive means adapted to be engaged by the material as it leaves said stretching chamber and to control the pressure of the said softening medium in said chamber, causing said pressure to vary with the tension in the material engaging with said tension-sensitive means.

9. Apparatus according to claim-8 comprising an adjustable controller for regulating the admission of softening medium to the stretching chamber so as to maintain a determined but correspondingly adjustable pressure in said chamber, the adjustment of said controller being effected by the tension-sensitive means.

10. Apparatus according to claim 8 comprising a relay for amplifying the force applied by the tension in the material to the tension-sensitive means, in order to effect control of the pressure in the stretching chamber.

11. Apparatus according to claim 8 comprii ing a member loaded in one direction an. adapted to be urged in the opposite direction by the tension in the material, a valve for a supply of compressed air, said valve being regulated by the motion of said member, and adiaphragm exposed on one side to compressed air supplied through said valve, said diaphragm being capable of exerting a force varying with but greater than the force applied to said member;

12. Apparatus according to claim 8 compris- 5 stretch required, said means being caused tofunction by the tension in the material being stretched. r

13. Apparatus according to claim 8 comprising a feed chamber preceeding the stretching chamber and means for controlling the pressure in said feed chamber in accordance. with the pressure in said stretching chamber, said controlling means including a tension-sensitive device operated by the tension in thematerial being stretched.

14. Apparatus for stretching textile materials in the form of fllaments'or threads while they are running through a softening medium, said apparatus comprising a stretching chamber, means for supplying a softening medium to said stretching chamber, a rotatable drawing member adapted to draw the material after it has left said chamber, a tension-sensitive device in the neighborhood of said member adapted to deflect the material through an angle and to move under variations in the tension in the deflected material, a relay actuated by the motion of said device, and variable speed driving means for said member under the control of said relay, adapted on variation of the tension in the material to vary the speed of rotation of said member in such a sense as to counteract said variations.

. 15. Apparatus according to claim 14 comprising, as the relay, a value actuated by the movable device and adapted to control a flow of fluid under pressure, a leak permitting the escape against a resistance of fluid passing through said valve, and a movable member'having a substantial surface exposed to the pressure of said fluid behind said leak, the movement of said member controlling the variable speed driving means.

16. Apparatus according to claim 14 comprising a valve for varying the resistance offeredby the leak to the escape of fluid, said valve being coupled with the valve actuated by the movable device in such a manner as to increase said resistance as the latter valve is opened.

17. Apparatus according to claim 14 wherein the rotatable drawing member is a stretching roller for drawing the material from the stretching chamber, and wherein the tension-sensitive device causes the speed of said roller-to increase 0; decrease for the starting or stopping of the stretching operation. I

18. Apparatus according, to claim 14 wherein the rotatable'drawing member is a winding spindie for the winding of the stretched material, and wherein the tension sensitive device causes the speed-of said spindle to decrease as the material is wound, so that the material is wound at sub- 5 stantially constant tension.

MAITLAND WALTON ALFORD. THOMAS JACKSON. FRANK BRENTNALL HJILU 

